Update ci.yml

Author: wellyshen

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: Use Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v2.1.5
+        uses: actions/setup-node@v2
         with:
           node-version: ${{ matrix.node-version }}